RSAA Colloquia / Seminars / Feast-of-Facts: Friday, 08 July 2016, 14:00-15:00; Duffield Lecture Theatre

I-Ting Ho

"Gas flows in star-forming galaxies in the era of 3D spectroscopy"

I will be presenting my dissertation work done in the past three years at the RSAA/ANU and the Institue for Astronomy/University of Hawai’i. Gas flows are one of the fundamental processes driving galaxy evolution. This thesis explores gas flows in local galaxies by studying metallicity gradients and galactic-scale outflows in normal star-forming galaxies. This is made possible by new integral field spectroscopy data that provide simultaneously spatial and spectral information of galaxies. With the new 3D data, I study metallicity gradients and galactic winds to understand inflows and outflows in star-forming galaxies. I show that metallicity gradients in isolated disk galaxies are remarkably simple and universal. Simple chemical evolution models reveal that these simple metallicity gradients are a direct result of the coevolution of gas and stellar disk while galactic disks build up their masses from inside-out. Tight constraints on their mass outflow rates and inflow rates can be placed. I also investigate galactic winds in normal star-forming galaxies using data from the SAMI Galaxy Survey. I show that galactic winds are found to be very common even in normal star-forming galaxies that were not expected to host winds. By comparing galaxies with and without hosting winds, I show that galaxies with high star formation rate surface densities and bursty star formation histories are more likely to develop large-scale galactic winds.